Just curious
2002 F150 4.2 V6 No compression cylinder 2,
removed both rockers and push rods and still slight leak from throttle body while performing leak down test.
Vacuum test, needle bounces between 15 and 18 in, pretty much steadily.
Now, when I performed my compression check, it showed no compression (under 30), but when I removed rockers and connected air for leak down test, the engine rotated. (All plugs removed)
ANY IDEAS?

 

Valve burned?

 

I would borescope it. Sure does sound like a valve problem to me - burned or stuck.

 

Thanks for the input, will do later this week